The present invention relates to adhesion regulation during deposition processes. The present invention also relates to fabrication of MEMS devices. The present invention also relates to increasing the component density in semiconductor devices.
WO99/13562 and U.S. Pat. No. 6,417,060 disclose applications for which it is beneficial to have two separated surfaces which substantially mirror each other, and methods for making pairs of electrodes whose surfaces replicate each other are disclosed therein. The methods involve fabricating a composite by providing a first electrode with a substantially flat surface and placing a sacrificial layer over it. A second material, which will form the second electrode, is placed over the sacrificial layer. The composite is then ‘split’ into two matching electrodes by removing the sacrificial layer by etching, by cooling the sandwich with liquid nitrogen, or by heating to evaporate the sacrificial layer.
U.S. Pat. No. 6,232,847 discloses a high-Q precision integrated reversibly trimmable single-band oscillator using either a MEMS switching network to selectively interconnect fixed inductors or capacitors or reversibly trimmable MEMS inductors or capacitors to trim the resonant frequency of the local oscillator signal. The MEMS switching network is fabricated using layered deposition regimes involving sacrificial layers.
U.S. patent application Ser. No. 2003/0006468 discloses a method comprising forming a plurality of three dimensional first structures over an area of a substrate. Following the formation of the first structures, the method also includes conformally introducing a sacrificial material over the substrate. A second structural material is then introduced over the sacrificial material followed by the removal of the sacrificial material. The conformal introduction (e.g., deposition) and removal of sacrificial material may be used to form narrow gaps (e.g., on the order of the thickness of the introduced sacrificial material). Accordingly, the method is suitable, in one context, for making microelectromechanical structures (MEMS). Further, the gaps may be formed by deposition and removal of sacrificial material without photolithography steps.
U.S. Pat. No. 6,600,252 discloses several MEMS-based methods and architectures which utilize vibrating micromechanical resonators in circuits to implement filtering, mixing, frequency reference and amplifying functions.
U.S. Pat. No. 6,670,864 discloses a matching circuit for adapting an amplifier to load impedance at various output power levels of the amplifier, and a method for adapting the amplifier to load impedance at various output power levels of the amplifier. The matching circuit comprises an LC circuit, i.e. an electric circuit switching consisting of at least one coil and at least one capacitor for tuning harmonic signals resulting from amplifier non-linearities. At least one capacitor of the LC circuit is an adjustable microelectromechanical (MEMS) capacitor.
These MEMS-based approaches utilize components fabricated using layered deposition regimes involving sacrificial layers. Drawbacks of using sacrificial layers include incomplete removal of the sacrificial layer, and/or damage to one of both of the surfaces by the techniques in contact with the sacrificial layer.